ANGLES

THIRD GRADE

TYPES OF ANGLES

Look around and you'll start to notice lots of places where two line segments cross or meet each other at a point.

INTRO

In this lesson, let's learn more about angles!

In geometry, when two lines, line segments, or rays meet each other, they make an angle.

Now...

The amount of turn between two lines, line segments or rays around a common point is called the angle between them.

WHAT IS AN ANGLE?

A 90° angle is called a right angle. A right angle is marked by drawing a square at the vertex.

RIGHT ANGLE

For example

Windows and books have right angles.

An angle between 0° and 90° is called an acute angle.

ACUTE ANGLE

Pizza slices and party hats have acute angles.

FOR EXAMPLE

An angle that is greater than 90° but less than 180° is called an obtuse angle.

OBTUSE ANGLE

For example

Roofs of houses and parts of beehives have obtuse angles.

A 180° angle is called a straight angle. When the arms of the angle lie in the opposite direction, they form a straight angle. The angles make a straight line through the vertex.

STRAIGHT ANGLE